Your fact pattern is a bit confusing -- especially as to what happened when, and how much time has passed. If that stipulation and order is at least 3 years old, it is time to revisit it anyway; if it is not, but the underlying facts -- as to custody OR income -- have radically changed, a new order based on the current facts can and should be entered based on "changed circumstances."
For background, see the materials posted at http://willicklawgroup.com/child-support/. For a more precise evaluation of what you can do, take all paperwork done so far, and the current facts, to a family law specialist for a consultation; it should be possible to pretty precisely predict how a motion would be received and end up.
Answered on May 05th, 2015 at 9:12 AM